When detective Eric Matthews is called to a crime scene of a victim of Jigsaw, he finds a lead to the place where he is hidden. Once there, he realizes that Jigsaw trapped his son Daniel Matthews with three women and four men in a shelter, and they are inhaling a lethal nerve gas. If they do not use an antidote within two hours, they will die. Eric follows with increasing desperation the death of each member of the group in monitors, while trying to convince Jigsaw to release his son.

In France, terrorist groups and intelligence agencies battle in a merciless war everyday, in the name of radically opposed ideologies. Yet, terrorist and secret agents lead almost the same lives. Condemned to secrecy, these masters of manipulation follow the same methods. Alex and Al Barad are two of them. The former is the head of the D.G.S.E.'s (Direction Générale de la Sécurité Extérieure, the French equivalent of the CIA or the MI6) counter-terrorism unit while the latter reigns over a terrorist network, and both fight using the most ruthless of weapons: human beings. Secret Défense (aka Secrets Of State) tells of their secret war through the destinies of Diane, a student recruited by the French secret service, and Pierre, a troubled young man who thinks terrorism will bring him salvation. Trained and indoctrinated for missions which are beyond them, they are both drawn into a chain of events from which they seem incapable of escaping...